1. Field of the Invention
The present invention relates to a discharge tube, a ferrule, a lighting device, a display device and a television receiver.
2. Description of the Related Art
An example of a discharge tube that can be applied to a lighting device is disclosed in JP-A-H08-082798. The discharge tube includes a cylindrical glass tube sealed airtight, and further includes metallic ferrules having a cylindrical shape to be fitted onto the outer circumference of the end portion of the glass tube.
In the above discharge tube, the ferrules are mounted to the glass tube so as to have intimate contact with the outer circumferential surface thereof. However, glass tubes usually have inevitable variations in outer diameter, due to manufacturing reasons. The control of outer diameter for glass tubes with high precision involves high manufacturing cost.